Climate science - Sept 23

Record sea ice melt this summer larger than Texas and AlaskaJane Kay, San Francisco Chronicle Shattering previous records, the sea ice in the Arctic shrank 1 million square miles more this summer than the average melt over 25 years, an area larger than Alaska and Texas combined, according to NASA satellite data released Thursday.

Scientists at the federally financed National Snow and Ice Data Center at the University of Colorado attributed the big melt to a global increase in ocean and air temperatures. The melting was made worse by a cloudless summer in the Arctic, the researchers said.

"The Arctic sea ice is the first signal, and the biggest signal, of the effects of rising global temperatures," said Walt Meier, a research scientist at the center.

Data show the sea ice also is thinner. It's breaking up earlier in the spring and is freezing over later in the fall. There are more days with greater expanses of open water. (21 September 2007)

Scientists have long sought to understand the triggers for an extraordinary warming episode called the Palaeocene-Eocene Thermal Maximum (PETM), which occurred about 10 million years after the twilight of the dinosaurs.

Earth's surface warmed by at least five degrees Celsius (nine degrees Fahrenheit) in just a few hundred or a few thousand years.

...Richard Pancost, a researcher at Britain's University of Bristol [wrote]in the British journal Nature [that he believed] that the methane had remained locked up in the soil for millions of years before warming released it into the atmosphere. (19 September 2007)

African deluge brings misery to 1.5m peopleJohn Vidal in Soroti, Uganda; The Guardian The small plane banks steeply to the east and the extent of the floods in the low-lying Teso region of Uganda become clear: mile upon mile of low-lying pasture land submerged, tens of thousands of acres of staple crops like cassava, millet and groundnuts waterlogged. There are impassable roads, overflowing rivers, stranded cattle and devastated bridges. Villages are cut off and mud houses and roads have been swept away.

But this is a fraction of the devastation caused by some of the heaviest rains in memory to have hit a great swath of Africa from the Sahel to the horn.

According to the UN yesterday, 18 of the poorest and normally driest countries in Africa, from Senegal, Mauritania, Mali and Burkina Faso in the west, to Kenya, Sudan and Ethiopia in the east, have been seriously hit by months of torrential rains which, meterologists forecast, will continue in places for many more weeks.

"We believe at least 650,000 homes have been destroyed, 1.5 million people affected and nearly 200 people so far drowned," said Elisabeth Brys, at the UN Office for the Coordination of Humanitarian Affairs (Ocha) in Geneva. "This is harvest time for many countries and there are already food shortages."

The rains, linked to ocean temperature changes of El NiÃ±o, have caught governments off guard. Many of the worst affected regions are remote from capitals and assessments are still being made. (20 September 2007)Related audio and Podcast by Vidal.

The North Pole Is MeltingDavid Biello, The Scientific American The permanent Arctic ice cap dwindled to a record low this week, presaging a future of a summertime Northwest Passage and obscuring fog --- 'Tis the season in the Arctic when the sun disappears below the horizon and twilight replaces daylight. Temperatures drop and ice that melted throughout the Arctic summer begins to cover the world's northernmost ocean again. Scientists have used satellite pictures since 1979 to map the extent of such ice at its minimum, and the picture this year isn't pretty. Covering 1.59 million square miles (4.12 million square kilometers), this summer's sea ice shattered the previous record for the smallest ice cap of 2.05 million square miles (5.31 million square kilometers) in 2005-a further loss of sea ice area equivalent to the states of California and Texas combined.

"The sea ice cover this year has reached a new record low," says Mark Serreze, senior research scientist at the U.S. National Snow and Ice Data Center in Boulder, Colo. "It's not just that we beat the old record, we annihilated it."

NOT SO COLD FACT: This year's summer ice cover, represented in white, is slightly more than 1 million square miles smaller than the long-term average, represented by the pink line.(Image: NATIONAL SNOW AND ICE DATA CENTER)

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